1. Field of the Invention
The present invention relates to a novel amino butanol derivative and a process for the production of 3-pyrrolidinol from said aminobutanol derivative. More particularly, the present invention relates to a process for the effective and economical production of 3-pyrrolidinol or its salt and an aminobutanol derivative or its salt which is useful as an intermediate in the production of 3-pyrrolidinol.
3-Pyrrolidinol is an important intermediate in the production of a calcium-blocker or .delta.-lactam antibiotics.
2. Description of the Related Art
For the preparation of 3 pyrrolidinol, following processes are known:
(1) a process comprising hydroxylating a N-substituted-3-pyrroline of the formula: ##STR2## by hydroboration to obtain a 3-pyrrolidinol derivative of the formula: ##STR3## (see, for example, J. Org. Chem., 51, 4296 (1986) and Syn. Comm., 13, 1117 (1983)),
(2) a process comprising synthesizing 1-benzylmalic acid imide of the formula: ##STR4## wherein Bz represents a benzyl group, from malic acid of the formula: ##STR5## and reducing the 1-benzylmalic acid imide (V) to obtain 1-benzyl-3-pyrrolidinol of the formula: ##STR6## wherein Bz is the same as defined above (see Syn. Comm., 15, 587 (1985)), and
(3) a process comprising decarboxylating hydroxyproline of the formula: ##STR7## to obtain 3-pyrrolidinol (see Chem. Let., 893 (1986)).
Among the above processes, the process (1) utilizing the hydroboration and the process (2) using malic acid as the starting compound use comparatively expensive reagents such as diborane or lithium aluminum hydride. In the process (2), when optically active malic acid is used as the starting compound, since the compound is partly racemized during cyclization, the product should be subjected to optical resolution to obtain optically pure 3-pyrrolidinol.
The process (3) comprising decarboxylation of hydroxy proline has a drawback that the starting material proline is expensive.
Therefore, none of these three conventional processes is a commercially attractive one.